This invention relates to a piece of equipment designed to test the integrity of the package for a product which must be hermetically sealed. There are a variety of container types and packages which are capable of protecting the product therein and preventing the transmission of air and the like to and from the product. Such containers and packages include metal cans, flexible pouches, waxed paper containers, bottles, bags, vials, cartons, strip packages, blisters, pouches and the like. Once a product is placed inside such a container and hermetically sealed therein, there generally remains a head space between the product and the package. This head space can be pressurized in, for example, a soda pop container or can be under vacuum in, for example, a food retorded container; or it can be at ambient pressure.
No matter what the initial internal pressure condition of the package, a test should be performed to determine the integrity of the package. Without proper testing, safety and product quality problems will occur without notice and correction. Such testing equipment is sometimes used prior to packing to see that there are no pinholes or the like in the container. Similarly, there are tests such as "Dud Detectors" which examine one flexible end of a metal can by checking the flexure of same. If the end flexes under mechanical load, it is an indication that a proper vacuum has not been achieved inside the retorted food container. This technique has been used as well in connection with home canning to test the integrity of the seal of the lid rings and caps after the retorting of the canned foodstuff. Such a test is adequate for the semi-rigid end of a rigid container; however, that type of test is inadequate for soft or flexible containers and would be inappropriate to use in connection with a variety of the low cost flexible plastic packages now readily available. Certainly visual inspection of the package is impractical in a high-speed commercial environment.
It, therefore, becomes an object of the present disclosure to teach a means by which any type of container with at least one flexible end can be examined whether the container is to be internally pressurized or externally pressurized, i.e., under vacuum.
It is a further object of the invention disclosed herein to provide container testing which is foolproof, can be operated at high speed, and provide an automatic control and operating system using computer technology.
With the foregoing problems of the prior devices fully understood and appreciated, it is intended herein to disclose the means by which the package integrity for a hermitically sealed product, for its primary package, or for the overpack can be quickly and properly analyzed to determine whether an adequate seal has been achieved and has been maintained. The device disclosed herein is useful not only in the initial packaging, but in subsequent testing to determine shelf life of the product. The details of the preferred embodiment will be fully described herein in connection with its construction and operation.